Herbicidal compositions

ABSTRACT

This invention relates to a herbicidal composition comprising N-phosphonomethylglycine and/or a salt thereof and an alkyldiamine tetraalkoxylate surfactant, a surfactant composition useful in glyphosate compositions and a method for controlling or eradicating unwanted plants or vegetation.

This application has been filed under 35 USC 371 as a national stageapplication of international application PCT/AU97/00832 filed Dec. 5,1997.

This invention relates to herbicide formulations, in particular toherbicide compositions comprising N-phosphonomethylglycine (glyphosate)herbicides and alkyldiamine tetraalkoxylate surfactants. The inventionalso relates to a surfactant composition comprising an alkyldiaminetetraalkoxylate surfactant and an alkyl glycoside or alkylpolyglycosidesurfactant and its use with glyphosate herbicides, and to water solubleor water dispersible granules comprising a non-hygroscopic salt ofglyphosate and a solid alkyldiamine tetraalkoxylate surfactant.

N-phosphonomethylglycine, commonly known as “Glyphosate”, and its saltsare well known non-selective systemic herbicides, first developed in theearly 1970s by Monsanto Company. After absorption through the foliage itis rapidly translocated to regions of metabolic activity, including theroots and shoots. It has been found that formulation of glyphosate withsome surfactant adjuvants can lead to enhancement of herbicidalactivity.

Wyrill and Burnside, Weed Science Vol. 25 (1977), 275-287, conducted astudy of the effects of different surfactants on the herbicidal actionof glyphosate. Some classes of surfactant were more effective thanothers in enhancing the herbicidal effect of glyphosate (in particularas a solution of the isopropylamine salt).

Despite this study and subsequent attempts to correlate glyphosateactivity enhancement with surfactant structure, the effectiveness ofsurfactants with glyphosate is variable and difficult to predict.

The most commonly used surfactant adjuvants in glyphosate formulationsare the tallow amine ethoxylates. While these surfactants are veryeffective in enhancing the activity of glyphosate, they have recentlybeen shown to have significant aquatic toxicity. Accordingly in manyregions the use of glyphosate compositions comprising tallow amineethoxylates in proximity to waterways and catchment areas has beenseverely regulated. In particular it has been shown that about 3 ppm ofa standard ethoxylated tallow amine/glyphosate formulation has an acutetoxic effect on Daphnia carinata according to a standard 48 hour EC₅₀test.

It has now been surprisingly found that the use of alkyldiaminetetraalkoxylate as a surfactant in a glyphosate compositions providesglyphosate formulations with activity comparable to the knownglyphosate/ethoxylated tallow amine compositions, and which exhibit lowaquatic toxicity.

According to a first aspect of the present invention there is provided aherbicide composition comprising N-phosphonomethylglycine and/or a saltthereof and an alkyldiamine tetraalkoxylate surfactant.

As used herein, “glyphosate composition” means N-phosphonomethylglycineas well as any composition or formulation containing a glyphosateherbicide. “Glyphosate herbicide” means any form of glyphosate which inaqueous solution provides glyphosate anions along with suitable cationsor glyphosate acid. Glyphosate herbicide includes the isopropylaminesalts of glyphosate and other agriculturally acceptable salts ofglyphosate such as those disclosed in U.S. Pat. No. 3,799,758.

Examples of such suitable cations are alkali metal cations, for instancesodium and potassium, and ammonium and substituted ammonium cations. Thelatter include cations derived from primary or secondary amines such asisopropylamine or dimethylamine, and from diamines such asethylenediamine.

Further, examples of agriculturally acceptable salts of glyphosate aretrimethyl-sulfonium salt (“sulfosate”) or aminoguanidine salts asdisclosed in EP-A-0 088 180. Because glyphosate has more than onereplaceable hydrogen atom, mono- and di-salts are possible, as well asmixtures of such salts. Typical glyphosate salts are the sodium,ammonium and trimethylsulphonium salts as well as the mixedalkylsulfonium salts and trialkyl salts.

It has been found that the surfactant adjuvants of the present inventionhave an efficacy which is comparable to the standard tallow amineethoxylates currently in use. This is surprising since the hydrophobe intallow amine is a mixture of fatty monoamines with a carbon chain linkof 16 to 18 units. In contrast the base hydrophobe of the surfactants ofthe present invention is a diamine of a short C1-C₆ alkyl chain. Inaddition the hydrophilic portions of the tallow amine contain onlyethoxylate whereas the surfactant of the present invention may containsome higher alkoxylate groups.

In addition it would not be expected that the surfactants of the presentinvention would have a low toxicity profile from their structure. It isalso unexpected that the surfactants of the present invention wouldperform as well as tallow amine as an adjuvant for glyphosate. All thatthe two hydrophobes have in common is an amine functionality, this aminefunctionality not having been previously identified as important forsuitability for use with glyphosate. It has generally been consideredthat it is the alkyl chain function which is more important. It wastherefore not expected that a short chain diamine would function as wellas a long chain monoamine.

On the basis of their structure alkyldiamine tetraalkoxylate surfactantswould not be expected to be compatible with the high salt and low pHenvironment of an aqueous glyphosate composition, and accordingly it issurprising that they are useful adjuvants for glyphosate herbicides.

The term “low aquatic toxicity” is used herein in connection with thesurfactants or herbicide compositions of the present invention to referto an acute aquatic toxicity less than the toxicity of an equivalentcomposition comprising an ethoxylated tallow amine as the surfactantcomponent. The term also indicates that the toxicity of the surfactantor composition is sufficiently low to satisfy local, regional ornational regulations governing the toxicity of surfactants or herbicidecompositions in the locality, region or country in which the surfactantor composition is used. The herbicide compositions according to thepresent invention preferably meet a standard EC₅₀ or LC₅₀ test inrespect of a suitable indictor organism, for example Daphnia speciessuch as Daphnia carinata, at a concentration of 100 ppm, more preferably300 ppm, and most preferably 1000 ppm.

In addition to the advantages of low aquatic toxicity and efficacy ofalkyldiamine tetraalkoxylates as surfactants with glyphosateformulations, they also possess advantages over other surfactants whichhave been used with glyphosate formulations, such as ease of handling,and a lower foaming profile than some other surfactants currently used.

In a preferred embodiment the alkyldiamine tetraalkoxylate surfactantcomprises a compound of formula (I):

wherein Q is a linear or branched C₁-C₆ alkylene, and each R isindependently selected from oxyalkylene polymer or block copolymerchains.

Q is preferably —(CH₂)_(n)— where in n is 2 to 6 or a branched alkylenegroup having 3 to 6 carbon atoms such as

Most preferably Q is ethylene.

R may be a polymer of an oxyalkylene group such as oxyethylene,oxypropylene or oxybutylene. R may be a block copolymer of two or moredifferent oxyalkylene groups such as oxyethylene, oxypropylene oroxybutylene. It is preferred that R is a block copolymer of oxyethyleneand oxypropylene.

The blocks may alternative in the chain. For example compounds offormula (I) may be made by starting with a compound of formula (II):

wherein A is an alkylene group. The compound of formula (II) may then becondensed with an alkylene oxide wherein the alkyl group may be the sameor different to A. The resulting compound may be further condensed witha different alkylene oxide and so on to give the final compound.

In a further preferred embodiment, the surfactants of the presentinvention have the following formula (III):

wherein A and B are different C₂-C₄ alkylene groups,

R is H or C₁-C₆ alkyl, and

X and Y are integers from 0 to 150, provided X and Y are not both zero.

Preferably A is propylene and B is ethylene, or A is ethylene and B ispropylene.

Where A is propylene and B is ethylene, X is preferably an integer from1 to about 30, more preferably about 4 to about 25, and Y is preferably0 to about 150, more preferably about 4 to about 120.

Most preferred surfactants of the present invention are ethylene diaminealkoxylate of the following formula (IV):

wherein x and y are as defined above.

C₂H₄O will hereinafter be referred to as EO and C₃H₆O as PO.

Suitable alkyl diamine alkoxylates which may be used as surfactants arethe SYNPERONIC T series and TERIC 173 which are commercially availableethylene diamine alkoxylates. Particularly suitable are SYNPERONIC T/304and TERIC 173. SYNPERONIC T/304 and TERIC 173 are compounds of formula(IV) wherein x and y are 4. Also suitable are SYNPERONIC T/707 which isa compound of formula (IV) wherein x is 16 and y is 50, SYNPERONIC T/908which is a compound of formula (IV) wherein x is 22.5 and y is 118 andTERIC 170 which is a compound of formula (IV) wherein x is 1 and y is 4.

It has been unexpectedly found that the incompatibility between thealkyldiamine tetraalkoxylate surfactant and glyphosate herbicide inconcentrated solution can be overcome or alleviated by increasing thesolubility of the surfactant by reducing the size of the oxyalkylenepolymer or block copolymer chains. It is further surprising that inreducing the size of the oxyalkylene polymer or block copolymer chainthat the efficacy and aquatic toxicity profile of the resultingformulations remains acceptable.

Accordingly in a second aspect the present invention provides aherbicide composition comprising N-phosphonomethylglycine and/or a saltthereof, and an alkyldiamine tetraalkoxylate surfactant, wherein thealkyldiamine tetraalkoxylate surfactant comprises a compound of formula(III) as defined above in which X and Y are integers from 0 to 5,provided X and Y are not both 0 and that X+Y is less than or equal to 6.

In a preferred embodiment of this aspect of the invention thealkyldiamine tetraalkoxylate surfactant comprises a compound of formulaIII where A is propylene, B is ethylene, R is hydrogen, X is 1 to 3, Yis 3 to 5, provided X+Y is 4 to 6.

In a particularly preferred embodiment X is 1 and Y is 4.

These alkyldiamine tetraalkoxylate surfactants have been found to beunexpectedly and surprisingly compatible with glyphosate in both low andhigh strength compositions. In particular the surfactants have beenfound to be compatible with horticultural/industrial type formulations(containing for example 360 g/l of glyphosate acid equivalent) and broadacre use formulations (containing for example 450 g/l of glyphosate acidequivalent).

It has also been surprisingly found that the incompatibility between theglyphosate herbicide and the alkylamine tetraalkoxylate surfactant canbe overcome or alleviated by formulating the composition as a watersoluble or water dispersible granule.

This involves using a non-hygroscopic salt of N-phosphonomethylglycine,such as an ammonium salt, together with a solid form of alkyldiaminetetraalkoxylate surfactant.

Accordingly in another aspect of the invention there is provided aherbicide composition in the form of water dispersible or water solublegranules comprising a non-hygroscopic salt of N-phosphonomethylglycineand an alkyldiamine tetraalkoxylate surfactant having a melting point orsoftening point greater than 45° C., preferably greater than 50° C.

It has been found that increasing the size of the oxyalkylene polymer orblock copolymer chain increases the melting point or softening point ofthe alkyldiamine tetraalkoxylate surfactant.

Preferably the alkyldiamine tetraalkoxylate surfactant comprises acompound of formula (III) as defined above in which X and Y are integersfrom 0 to 150, provided X+Y is greater than or equal to 50. In aparticularly preferred embodiment A is propylene, B is ethylene, X is 10to 30 and Y is 50 to 150.

The water soluble or water dispersible granules may be prepared inaccordance with standard methods known to the art, such as pan or drumgranulation, extrusion, fluid bed or spray drying, or compaction ortabletting. The solid granules have the advantages of allowing highconcentrations of active and surfactant, improved storagability andtransportability, ease of measuring quantities of compositions and ofcleaning of spills, and other advantages generally associated with solidformulations.

It has also been surprisingly found that the surfactant according to theinvention can be used in conjunction with an alkyl glycoside oralkylpolyglycoside surfactant. In addition to acting as a hydrotrope forthe alkyldiamine tetraalkoxylate surfactant, and thereby improving thecompatibility of the alkyldiamine tetraalkoxylate surfactant with theglyphosate herbicide, the alkylglycoside or alkylpolyglycosidesurfactant exhibits a synergistic effect with the alkyldiaminetetraalkoxylate surfactant to provide a glyphosate composition having anactivity comparable to a glyphosate composition comprising the standardethoxylated tallow amine surfactant. It has also been unexpectedly foundthat the presence of the alkyldiamine tetraalkoxylate surfactant withthe alkylglycoside or alkylpolyglycoside surfactant reduces the foamingcharacteristics of the alkylglycoside or alkylpolyglycoside surfactant.

Accordingly in a further aspect of the present invention there isprovided a herbicide composition comprising N-phosphonomethylglycineand/or a salt thereof, an alkyldiamine tetraalkoxylate surfactant, andan alkylglycoside or alkylpolyglycoside surfactant.

The terms “alkylglycoside” and “alkylpolyglycoside” as used herein referto alkylglycosides of glucose or other monosaccharides, ordisaccharides, for example, sucrose, or of polysaccharides. These may beobtained by reaction of alkanols with the mono, di or polysaccharides.The term also includes surfactants prepared from mixtures ofmonosaccharides and disaccharides, as well as from mixtures of alkanols.Commercially available alkylglycosides and alkylpolyglycosides aregenerally the product of the reaction of glucose with a mixture ofalkanols containing 8 to 10 carbon atoms. The number of glycoside unitsper molecule (i.e. the DG ratio), can vary.

Examples of suitable alkylglycoside or alkylpolyglycoside surfactantssuitable for use in accordance with this aspect of the invention includeATPLUS 450, ATPLUS 258, ATPLUS 3001 A (Imperial Chemical IndustriesPLC), ECOTERIC AS1O, ALKADET 15 (ICI Australia), Triton BG (UnionCarbide), APG 300, APG 225 (Henkel), Staley APG 91-3, Staley APG 23-1and Staley APG 23-3 (Staley Corporation)

In order to reduce compatibility problems with the glyphosate herbicideit is preferable for the weight ratio of alkylglycoside oralkylpolyglycoside surfactant to alkyldiamine tetraalkoxylate surfactantto be between 1.2:1 and 2:1, more preferably about 1.5:1. It ispreferred that the combination of alkyl glycoside or alkyl polyglycosidesurfactants and alkyldiamine tetraalkoxylate surfactants is used inglyphosate compositions containing less than 400 g/L, more preferablyless than 360 g/L of glyphosate acid equivalent. For compositionscontaining a higher concentration of glyphosate it is preferable to usean alkyldiamine tetraalkoxylate of formula III.

It has been found that decreasing the size of the oxyalkylene polymer orblock copolymer chain to improve compatibility with the glyphosateherbicide can result in a lowering of the efficacy of a glyphosateherbicide, compared with an equivalent formulation in which the standardethoxylated tallow amine surfactant is used. However it has beenunexpectedly found that the use of an alkylglycoside oralkylpolyglycoside surfactant in combination with such an alkylaminetetraalkoxylate surfactant can bring the activity of the composition upto the level of the standard formulation. The combination of analkyldiamine tetraalkoxylate surfactant and an alkylglycoside oralkylpolyglycoside surfactant as described above is novel and representsa further aspect of the present invention.

The compositions of the present invention may be formulated as dusts,granular compositions, liquid emulsions or liquid concentrates. Thesurfactant may also be added to a spray tank solution of glyphosate,i.e.: be applied as a tank added solution. The compositions of thepresent invention may contain alkyldiamine tetraalkoxylate in an amountof up to about 90% of the weight of glyphosate free acid equivalentpresent in the formulation.

For use of alkyldiamine tetraalkoxylates as tank added adjuvants thereis essentially no upper limit on the amount of surfactant which may beadded but typically a surfactant would be used in an amount from0.025-0.6 kg per ha (on an active surfactant basis) depending on thestrength of the glyphosate used.

The compositions of the present invention may be used in the control oreradication of unwanted plants or vegetation by application to a locuswhere control is desired. Normally this would be on the foliage of theweed pests to be eradicated. Accordingly in yet another aspect of thepresent invention there is provided a method for controlling oreradicating unwanted plants or vegetation including the step of applyingto a locus where control or eradication is desired a phytotoxic amountof a herbicidal composition according to the invention described above.

The composition according to the invention will generally be diluted inwater before being sprayed or applied in another known manner on theplant species to be treated. The dilution may be such that conventionalspraying of 50-600 L/ha provides 0.125 to 3 kg of glyphosate acidequivalent per hectare. Spray solutions for controlled drop spraying aremore concentrated than for other applications.

The phytoactivity of herbicidal compositions also depends on thequantity of glyphosate used for treating the particular plant species;thus, the quantity of composition used is usually expressed in gramglyphosate acid equivalents per hectare. It has been found that 200-600grams acid equivalent per hectare have provided the most significantresults.

The compositions of the present invention may also contain otherconventional adjuvants normally formulated with glyphosate formulationssuch as anti-foaming agents, thickeners, heat stabilizers, ultravioletabsorbers, dispersants and fertilizers, and other agriculturallyacceptable materials, including fillers, such as talc, diatomaceousearth and the like, and diluents, such as water. The compositions mayalso contain additional surfactant adjuvants having low aquatictoxicity, provided the presence of such surfactants does not reduce theefficacy of the herbicidal compositions below acceptable levels.

For solid glyphosate compositions where the adjuvant is built-in analkyldiamine tetraalkoxylate of high molecular weight is preferablyused. The surfactant composition may be used up to a level of 100% byweight of glyphosphate present as free acid equivalent but moretypically at less than 35%.

The invention will now be described with reference to the followingexamples. However it is to be understood that the particularity of thefollowing examples is not to supersede the generality of the precedingdescription of the invention.

The invention will now be described with reference to the accompanyingexamples and drawings which illustrate some preferred embodiments of theinvention and some comparisons with commercial formulations. However itis to be understood that the particularity of the following descriptionis not to supersede the generality of the preceding description of theinvention.

In the drawings:

FIG. 1 is a comparison of the calculated ED₅₀ values (95% confidenceintervals shown by shading) for the compositions of Examples 1 and 6,and the commercial tallow amine ethoxylate based product (referred tothe figure as “Glyph 360”) on the grass weed, Ryegrass (Lolium rigidum).

FIG. 2 is a comparison of the ED₅₀ values (95% confidence intervalsshown by shading) for Example 4 (comparative example) and a standardtallow amine ethoxylate based formulation with the compositions ofExamples 6, 7 and 8 on Ryegrass.

FIG. 3 is a comparison of the calculated ED₅₀ values (95% confidenceintervals shown by shading) for the composition of Examples 9 and 10with two commercially available solid formulations on Ryegrass.

FIG. 4 is a comparison of the calculated ED₅₀ values 95% confidenceintervals shown by shading) for the compositions of Examples 9 and 10 onthe broadleaf plant Canola (Brassica napus L.)

FIG. 5 is a comparison of the calculated ED₅₀ values (95% confidenceintervals shown by shading) for the compositions of Examples 1, 2 and 6on Canola

EXAMPLES Example 1

A 360 g/L formulation of glyphosate present as the isopropylamine saltis formulated as follows:

Glyphosate isopropylamine salt (60% w/w) 810 g/L TERIC 170 170 Water tovolume.

(TERIC 170 is a commercially available compound of formula IV where x is1 and y is 4 as indicated in Table 1.)

The acute EC₅₀ aquatic toxicity data for TERIC 170 on Daphnia carinatais shown in table 2 and the bio-efficacy relative to the standard tallowamine ethoxylate formulation using a similar level of surfactant isshown on Table 3 and in another trial on Table 8. The relativebio-efficacy is also shown in FIG. 1 and FIG. 5. The data from FIG. 1indicates that the TERIC 170 is comparable to the tallow amineethoxylate on Ryegrass. TERIC 170 shows greatly reduced acute aquatictoxicity compared to tallow amine ethoxylate.

Example 2

A 360 g/L formulation of glyphosate present as the isopropylamine saltis formulated as follows:

Glyphosate isopropylamine salt (60% w/w) 810 g/L TERIC 171 170 Water tovolume.

(TERIC 171 is a commercially available compound of formula IV where x is12 and y is 4 as indicated in Table 1.)

The bio-efficacy relative to the standard tallow amine ethoxylateformulation is shown on Table 8. The relative bio-efficacy is also shownin FIG. 5. The acute aquatic toxicity of the formulation is greatlyreduced relative to the standard tallow amine ethoxylate formulationwith TERIC 171.

Example 3

A 360 g/L formulation of glyphosate present as the isopropylamine saltis formulated as follows.

Glyphosate isopropylamine salt (60% w/w) 810 g/L TERIC 172 170 Water tovolume.

(TERIC 172 is a commercially available compound of formula IV where x is3 and y is 4 as indicated in Table 1.)

Example 4 (Comparative example)

A 360 g/L formulation of glyphosate present as the isopropylamine saltmay is formulated as follows:

Glyphosate isopropylamine salt (60% w/w) 810 g/L ATPLUS 3001A 243 Waterto volume.

(ATPLUS 3001A is a commercially available alkylpolyglucoside surfactantas indicated in Table 1.) The level of active surfactant present is 170g/L.

The acute EC₅₀ aquatic toxicity data for ATPLUS 3001A on Daphniacarinata is shown in Table 2 and the bio-efficacy compared to thestandard tallow amine ethoxylate formulation is shown on Table 4. Therelative bio-efficacy is also shown in FIG. 2. ATPLUS 3001A has a higheracute aquatic toxicity than the alkyldiamine tetraalkoxylates.

Example 5

A 360 g/L formulation of glyphosate present as the isopropylamine saltis formulated as follows:

Glyphosate isopropylamine salt (60% w/w) 810 g/L ATPLUS 436 213 Water tovolume.

(ATPLUS 436 is a commercially available surfactant as indicated in Table1.) The active surfactant level present in the formulation is 170 g/L.

The acute EC₅₀ aquatic toxicity data for ATPLUS 436 in the aboveformulation on Daphnia carinata, Litoria Lesueuri and oncorhynchusmykiss is shown in Table 2. The bio-efficacy compared to the standardtallow amine ethoxylate formulation in glasshouse evaluations is shownon Tables 5A and 5B. The results indicate no significant difference inefficacy when compared to the standard tallow amine ethoxylate when usedat 360 g/L. The aquatic toxicity of the formulation using ATPLUS 436 ishowever significantly reduced.

Example 6

A 360 g/L formulation of glyphosate present as the isopropylamine saltis formulated as follows.

Glyphosate isopropylamine salt (60% w/w) 810 g/L DS 2529 206 Water tovolume.

(DS 2529 is a blend of TERIC 170 and ATPLUS 3001A as indicated in Table1.)

The acute EC₅₀ aquatic toxicity data for the above composition onDaphnia carinata, Litoria Lesueuri and oncorhynchus mykiss is shown inTable 2. The bio-efficacy compared to the standard tallow amineethoxylate formulation and TERIC 170 on ryegrass is shown on Table 3 andwith Canola on Table 8. Comparison with ATPLUS 3001A is shown in Table4. Its relative bioefficacy is shown in FIG. 1, FIG. 2 and FIG. 3. Theseresults indicate that the combination of ATPLUS 3001A and TERIC 170 hasresulted in same or better performance than the ATPLUS 3001A used aloneat the same rate. The results also indicate that the combination ofATPLUS 3001A and TERIC 170 has resulted in an efficacy result betterthan TERIC 170 alone while at the same time markedly improving theaquatic toxicity profile of the formulation.

Example 7

A 360 g/L formulation of glyphosate present as the isopropylamine saltis formulated as follows:

Glyphosate isopropylamine salt (60% w/w) 810 g/L DS 2547 192 Water tovolume.

(DS 2547 is a blend of TERIC 170 and ATPLUS 3001A as indicated in Table1.)

The bio-efficacy compared to the standard tallow amine ethoxylate isshown on Table 4 and its relative bioefficacy is shown in FIG. 2. Theseresults indicate that the combination of ATPLUS 3001A and TERIC 170 hasresulted in better performance on these ryegrass weeds than the ATPLUS3001A used alone at the same rate. The results also indicate that thecombination of ATPLUS 3001A and TERIC 170 has resulted in an efficacyresult better than TERIC 170 alone while at the same time it willmarkedly improve the aquatic toxicity profile of the formulation.

Example 8

A 360 g/L formulation of glyphosate present as the isopropylamine saltis formulated as follows:

Glyphosate isopropylamine salt (60% w/w) 810 g/L DS 2548 177 Water tovolume.

(DS 2548 is as indicated in Table 1.)

The bio-efficacy is shown on Table 4 and its relative bioefficacy isshown in FIG. 2. These results indicate that the combination of ATPLUS3001A and TERIC 170 has resulted in better performance than the ATPLUS3001A used alone at the same rate. The results also indicate that thecombination of ATPLUS 3001A and TERIC 170 has resulted in an efficacyresult better than TERIC 170 alone while at the same time markedlyimproving the aquatic toxicity profile of the formulation.

Example 9

A solid granular formulation of glyphosate present as the monoammoniumsalt is formulated as follows:

Glyphosate ammonium salt (96% w/w) 734 g/kg SYNPERONIC T/707 217Ammonium sulphate 49

(SYNPERONIC T/707 is a compound of formula IV where x is approximately16 and y is 50 as indicated in Table 1.)

The acute EC₅₀ aquatic toxicity data for Daphnia carinata is shown inTable 2 and its bio-efficacy relative to the commercially availablesolid formulations of Weedmaster™ (Nufarm) and Biactive™(Monsanto) ongrass and broadleaf weed species is shown in Tables 6 and 7. Weedmastercontains a urea-nonionic surfactant complex while Biactive is believedto contain a blend of alkylquaternaryaminealkoxylate and polysorbatesurfactants. The relative bio-efficacy of the product is shown in FIGS.3 and 4. From the data SYNPERONIC T/707 is significantly moreefficacious on grass weeds than the commercial formulations and at leastcomparable on broadleaf weeds.

Example 10

A solid granular formulation of glyphosate present as the monoammoniumsalt is formulated as follows:

Glyphosate ammonium salt (96% w/w) 734 g/kg SYNPERONIC T/908 217Ammonium sulphate 49

(SYNPERONIC T/908 is a compound of formula IV where x is approximately16 and y is 50 as indicated in Table 1.)

The acute EC₅₀ aquatic toxicity data for Daphnia carinata is shown inTable 2 and its bio-efficacy compared to the commercially availablesolid formulations as described in Example 9 on broadleaf and grass weedspecies is shown in Tables 6 and 7. The relative bio-efficacy of theproduct is shown in FIGS. 3 and 4. The data indicates that theSYNPERONIC T/908 formulation is comparable in efficacy to Weedmaster andsignificantly better than Biactive in the ryegrass weeds. The SYNPERONICT/908 formulation is at least comparable with Weedmaster formulation onthe Canola weeds. The formulation using SYNPERONIC T/908 will beexpected to have a significantly better aquatic toxicity profile thanthe Weedmaster sample tested based on comparative results for thesurfactant type used.

TABLE 1 Product MW - Compositions No mol No mol Product PO EO Base %Surfactant MW TERIC 170 4 16 Ethylene diamine 100  996 TERIC 171 8 16Ethylene diamine 100 1228 TERIC 172 12 16 Ethylene diamine 100 1460TERIC 173 16 16 Ethylene diamine 100 1692 ATPLUS 3001A — — C8-C10alcohol  70 — ATPLUS 436 — — Blend: ATPLUS 3001A  68 — (DS 2320) TERIC173  32 DS 2529 Blend: ATPLUS 3001A  59 — TERIC 170  41 — DS 2547 Blend:ATPLUS 3001A  38 — TERIC 170  62 — DS 2548 Blend: ATPLUS 3001A  14 —TERIC 170  86 — SYNPERONIC T/707 63 200 Ethylene diamine 100 12500  (DS2533) SYNPERONIC T/908 90 472 Ethylene diamine 100 26000  (DS 2534)

TABLE 2 Aquatic Toxicity Data EC50 (ppm) Aquatic Species Tadpole WaterFlea (# Litoria Lesueuri Rainbow Trout Product (Daphnia Carinata)*Litoria ewingi) (oncorhynchus mykiss) TERIC 170 766 — — TERIC 173 2518— — ATPLUS 3001A 79 — — ATPLUS 436 210 2563#  806 In glyphosate 360 g/LDS 2529 In glyphosate 490 3230* 1080 360 g/L SYNPERONIC T/707 >100,000 —— SYNPERONIC T/908 93,000 — —

TABLE 3 Bio-efficacy data for Glyphosate 360 g/L Formulations Ryegrass(Lolium rigidum) ED50 gai/ha 95% Ci* Product Example No. ED50 LowerUpper TERIC 170 1 134 114  156 DS 2529 6 101 76 134 Glyph. 360 —  91 66125 *Ci-Confidence interval calculated for the ED50

TABLE 4 Bio-efficacy data for Glyphosate 360 g/L Formulations Ryegrass(Lolium rigidum) ED50 gai/ha 95% Ci* Product Example No. ED50 LowerUpper DS 2529 6 59 52 67 ATPLUS 3001A 4 62 53 72 DS 2547 7 58 50 67 DS2548 8 53 46 62 GLYPH 360 — 46 40 53 *Ci-Confidence interval calculatedfor the ED50

TABLE 5A RESULTS SUMMARY Annual ryegrass 9 DAT α 27 DAT α 28 DAT βAdjuvant I₅₀ L/ha L U I₅₀ L/ha L U I₅₀ L/ha L U Standard* 0.771 a 0.6290.913 0.089 a 0.074 0.103 0.058 ab 0.046 0.069 ATPLUS 436 0.969 a 0.7121.225 0.099 ab 0.090 0.109 0.055 ab 0.042 0.067 *Standard tallow amineethoxylate sold under trade mark ATLAS G3780A DAT = days after treatmentα = visual count β = fresh weight L and U denote lower and upper 95%confidence limits of the value I₅₀ I₅₀ is the dose in L/ha that willgive a 50% score on the rating system used. This is an approximation tothe dose that will give 50% control of the sprayed plants. Valuesfollowed by the same letter do not differ significantly at the 95%confidence level.

TABLE 5B Paterson's curse 9 DAT α 27 DAT α 28 DAT β Adjuvant I₅₀ L/ha LU I₅₀ L/ha L U I₅₀ L/ha L U Standard* 0.366 a 0.269 0.463 0.152 abc0.116 0.188 0.104 ab 0.055 0.153 ATPLUS 436 0.540 a 0.320 0.760 0.207 c0.169 0.245 0.109 b 0.082 0.135 *Standard tallow amine ethoxylate soldunder trade mark ATLAS G3780A DAT = days after treatment α = visualcontent β = fresh weight L and U denote lower and upper 95% confidencelimits of the value I₅₀ I₅₀ is the dose in L/ha that will give a 50%score on the rating system used. This is an approximation to the dosethat will give 50% control of the sprayed plants. Values followed by thesame letter do not differ significantly at the 95% confidence level.

TABLE 6 Bio-efficacy data for Ammonium Glyphosate Formulations Ryegrass(Lolium rigidum) ED50 gai/ha 95% Ci* Product Example No. ED50 LowerUpper SYNPERONIC T/707  9 41 33 51 SYNPERONIC T/908 10 62 52 73WEEDMASTER ® — 67 57 77 BIACTIVE ® — 87 73 102  *Ci-Confidence intervalcalculated for the ED50

TABLE 7 Bio-efficacy data for Ammonium Glyphosate Formulations Canola(Brassica napus L.) ED50 gai/ha 95% Ci* Product Example No. ED50 LowerUpper SYNPERONIC T/707  9 65^(a ) 57 74 SYNPERONIC T/908 10 75^(ab) 6487 WEEDMASTER ® — 84^(ab) 65 110  *Ci-Confidence interval calculated forthe ED50

TABLE 8 Bio-efficacy data for Glyphosate 360 g/L Formulations Canola(Brassica napus L.) ED50 gai/ha 95% Ci* Product Example No. ED50 LowerUpper TERIC 170 1 76 62 96 TERIC 171 2 73 69 77 DS 2529 6 47 45 50 GLYPH360 — 40 37 43 *Ci-Confidence interval calculated for the ED50

Those skilled in the art will appreciate that the invention describedherein is susceptible to variations and modifications other than thosespecifically described. It is to be understood that the inventionincludes all such variations and modifications. The invention alsoincludes all of the steps, features, compositions and compounds referredto or indicated in this specification, individually or collectively, andany and all combinations of any two or more said steps or features.

Throughout this specification and the claims which follow, unless thecontext requires otherwise, the word “comprise”, or variations such as“comprises” or “comprising”, will be understood to imply the inclusionof a stated integer or group of integers but not the exclusion of anyother integer or group of integers.

The claims defining the invention are as follows:
 1. A herbicidalcomposition comprising N-phosphonomethylglycine and/or a salt thereofand an alkyldiamine tetraalkoxylate surfactant.
 2. A herbicidalcomposition according to claim 1 wherein the alkyldiamine tetraalkoxysurfactant comprises a compound of formula (I):

where Q is a linear or branched C₁-C₆ alkylene, and each R isindependently selected from oxylalkylene polymer or block copolymerchains.
 3. A herbicidal composition according to claim 2 wherein thealkyldiamine tetralkoxylate surfactant comprises a compound of formula(III):

wherein A and B are different C₂-C₄ alkylene groups, R is H or C₁-C₆alkyl, and X and Y are integers from 0 to 150, provided X and Y are notboth zero.
 4. A herbicidal composition according to claim 3 wherein A ispropylene and B is ethylene, or A is ethylene and B is propylene.
 5. Aherbicidal composition according to claim 4 wherein: A is propylene B isethylene R is hydrogen, X is 1 to 3, Y is 3 to 5, provided X+Y≦6.
 6. Aherbicidal composition according to claim 5 wherein X is 1 and Y is 4.7. A herbicidal composition according to claim 1 in the form of a waterdispersible or water soluble granule.
 8. A herbicidal compositionaccording to claim 7 comprising a non-hygroscopic salt ofN-phosphonomethylglycine.
 9. A herbicidal composition according to claim8 wherein the salt of N-phosphonomethylglycine is an ammonium salt. 10.A herbicidal composition according to claim 8 or claim 9 wherein thealkyldiamine tetraalkoxylate surfactant has a melting point or softeningpoint greater than 45° C.
 11. A herbicidal composition according toclaim 10 wherein the alkyldiamine tetraalkoxylate surfactant has amelting point or softening point greater than 50° C.
 12. A herbicidalcomposition according to claim 1 further comprising an alkylglycoside oralkylpolyglycoside surfactant.
 13. A herbicidal composition according toclaim 12 wherein the weight ratio of alkylglycoside oralkylpolyglycoside surfactant to alkyldiamine tetraalkoxylate surfactantis between 1.2:1 and 2:1.
 14. A herbicidal composition according toclaim 13 wherein the ratio is about 1.5:1.
 15. A method for preparing aherbicidal composition comprising admixing N-phosphonomethylglycineand/or a salt thereof with a surfactant composition comprising analkyldiamine tetraalkoxylate surfactant and an alkylglycoside oralkylpolyglycoside surfactant.
 16. The method according to claim 15wherein the weight ratio of alkylglycoside or alkylpolyglycosidesurfactant to alkyldiamine tetraalkoxylate is between 1.2:1 and 2:1. 17.A method for preparing a herbicidal composition comprising admixingN-phosphonomethylglycine and/or a salt thereof with an alkyldiaminetetraalkoxylate surfactant.
 18. A method of controlling or eradicatingunwanted plants or vegetation including the step of applying to a locuswhere control or eradication is desired a phytotoxic amount of acomposition according to claim 1.